Hi, On Sat, Aug 1, 2015 at 3:52 PM, Heiko St?bner <heiko at sntech.de> wrote: > The dt code when creating the platform-devices assumes a 32bit dma mask and > expects the drivers to set the correct dma_masks (in of_dma_configure). But > from the original description this looks more like a limitation of the rk3288, > not the individual dwmmc, dwc2, etc. > > So from my cursory glance, ZONE_DMA seems to be the best solution. As you said > that this was investigated too, do you know if they encountered any obstacles > that resulted in not adjusting the dma zone? > > > @Jeffy: do you know how widespread this is? I.e. are socs like the rk3128 or > possibly more importantly the rk3368 also affected by this in 4GB > configurations? > > > If the rk3368 does it too, this might get "interesting". In one of the mails > about ZONE_DMA from september 2014, Arnd mentioned that there was a patch > about getting the zone size from devicetree floating around, but it doesn't > look like this landed. I don't actually know all the details of the problems since others investigated. I was just trying to quickly summarize what I could find in the internal bug for the benefit of the list... Sorry if that's not terribly helpful. :( -Doug
